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amnion
amnion An inner cellular layer (epithelium) surrounding the fluid-filled embryo sac of reptiles, birds, and mammals. The wall of this sac has two layers of epithelium, with mesoderm and coelomic space between. The outer layer is usually called the chorion. The amnion and chorion develop as folds in the ectoderm and mesoderm which grow up around the sides of the embryo, eventually covering it. The amniotic fluid within the sac provides a liquid environment for the embryo, necessary for animals that reproduce on land. It may also cushion the mammalian embryo against distortion by maternal organs pressing on it. Sometimes the term ‘amnion’ is applied to the entire embryo sac.
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MICHAEL ALLABY. "amnion." A Dictionary of Zoology. 1999. Encyclopedia.com. 10 Feb. 2012 <http://www.encyclopedia.com>. MICHAEL ALLABY. "amnion." A Dictionary of Zoology. 1999. Encyclopedia.com. (February 10, 2012). http://www.encyclopedia.com/doc/1O8-amnion.html MICHAEL ALLABY. "amnion." A Dictionary of Zoology. 1999. Retrieved February 10, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O8-amnion.html |
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amnion
am·ni·on / ˈamnēˌän; -ən/ • n. (pl. - or -ni·a / -nēə/ ) the innermost membrane that encloses the embryo of a mammal, bird, or reptile. DERIVATIVES: am·ni·ot·ic / ˌamnēˈätik/ adj. |
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"amnion." The Oxford Pocket Dictionary of Current English. 2009. Encyclopedia.com. 10 Feb. 2012 <http://www.encyclopedia.com>. "amnion." The Oxford Pocket Dictionary of Current English. 2009. Encyclopedia.com. (February 10, 2012). http://www.encyclopedia.com/doc/1O999-amnion.html "amnion." The Oxford Pocket Dictionary of Current English. 2009. Retrieved February 10, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O999-amnion.html |
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amnion
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"amnion." World Encyclopedia. 2005. Encyclopedia.com. 10 Feb. 2012 <http://www.encyclopedia.com>. "amnion." World Encyclopedia. 2005. Encyclopedia.com. (February 10, 2012). http://www.encyclopedia.com/doc/1O142-amnion.html "amnion." World Encyclopedia. 2005. Retrieved February 10, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O142-amnion.html |
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amnion
amnion A membrane that encloses the embryo of reptiles, birds, and mammals within the amniotic cavity. This cavity is filled with amniotic fluid, in which the embryo is protected from desiccation and from external pressure. See also extraembryonic membranes.
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"amnion." A Dictionary of Biology. 2004. Encyclopedia.com. 10 Feb. 2012 <http://www.encyclopedia.com>. "amnion." A Dictionary of Biology. 2004. Encyclopedia.com. (February 10, 2012). http://www.encyclopedia.com/doc/1O6-amnion.html "amnion." A Dictionary of Biology. 2004. Retrieved February 10, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O6-amnion.html |
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amnion
amnion (am-ni-ŏn) n. the membrane that forms initially over the dorsal part of the embryo but soon expands to enclose it completely within the amniotic cavity.
—amniotic (am-ni-ot-ik) adj. |
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"amnion." A Dictionary of Nursing. 2008. Encyclopedia.com. 10 Feb. 2012 <http://www.encyclopedia.com>. "amnion." A Dictionary of Nursing. 2008. Encyclopedia.com. (February 10, 2012). http://www.encyclopedia.com/doc/1O62-amnion.html "amnion." A Dictionary of Nursing. 2008. Retrieved February 10, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O62-amnion.html |
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amnion
amnion (anat.) caul. XVII. — modL. — Gr. amníon, dim. of amnós lamb.
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T. F. HOAD. "amnion." The Concise Oxford Dictionary of English Etymology. 1996. Encyclopedia.com. 10 Feb. 2012 <http://www.encyclopedia.com>. T. F. HOAD. "amnion." The Concise Oxford Dictionary of English Etymology. 1996. Encyclopedia.com. (February 10, 2012). http://www.encyclopedia.com/doc/1O27-amnion.html T. F. HOAD. "amnion." The Concise Oxford Dictionary of English Etymology. 1996. Retrieved February 10, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O27-amnion.html |
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amnion
amnion See AMNIOTIC.
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AILSA ALLABY and MICHAEL ALLABY. "amnion." A Dictionary of Earth Sciences. 1999. Encyclopedia.com. 10 Feb. 2012 <http://www.encyclopedia.com>. AILSA ALLABY and MICHAEL ALLABY. "amnion." A Dictionary of Earth Sciences. 1999. Encyclopedia.com. (February 10, 2012). http://www.encyclopedia.com/doc/1O13-amnion.html AILSA ALLABY and MICHAEL ALLABY. "amnion." A Dictionary of Earth Sciences. 1999. Retrieved February 10, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O13-amnion.html |
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